John Chrysostom

"For as ye in times past have not believed God, yet have now obtained mercy through their unbelief; even so have these also now not believed, that through your mercy they may also obtain mercy. For God hath concluded them all in unbelief, that He might have mercy upon all."

He shows here that those of the Gentiles were called first. Then, as they would not come, the Jews were elected, and the same result occurred again. For when the Jews would not believe, again the Gentiles were brought over. And he does not stop here, nor does he draw the whole to a conclusion at their rejection, but at their having mercy shown them again. See how much he gives to those of the Gentiles, as much as he did to the Jews before. For when ye, he would say, "in times past did not obey," being of the Gentiles, then the Jews came in. Again, when these did not obey, ye have come. However, they will not perish forever. "For God hath concluded them all in unbelief," that is, hath convinced them, hath shown them disobedient; not that they may remain in disobedience, but that He may save the one by the captiousness of the other, these by those and those by these. Now consider; ye were disobedient, and they were saved. Again, they have been disobedient, and ye have been saved. Yet ye have not been so saved as to be put away again, as the Jews were, but so as to draw them over through jealousy while ye abide.